Nanocrystalline of Y2O3 doped with Eu3+ at different concentrations and also core-shell of Y2O3 is prepared by wet chemical method using urea hydrolysis at low temperatures. XRD, TEM and FTIR are used to characterize the prepared nanoparticles. The sizes determined by XRD are well in agreement with TEM results. As-prepared samples show luminescence peak of Eu3+ transition 5D0 → 7F2 at 615 nm but annealed samples at 610 nm. Core-shell study of the nanoparticles show reduction in the luminescence intensity compared to the core particles.